Several recent publications have reported either superluminescence or amplified spontaneous emission in polymeric organic light emitters such as conjugated polymers. (N. Tessier et al., Nature 382, 695 (1996); F. Hide et al., Science 273, 1833 (1996)). The materials used in those emitters were spin-coated from a solution of the polymer or its chemical precursors. Optically pumped, stimulated emission from organic laser dyes, introduced into inert, spin-coated polymers or gels has been described in the literature. (R. E. Hermes, et al., Appl. Phys. Lett. 63, 877 (1993); M. N. Weiss et al., Appl. Phys. Lett. 69, 3653 (1996); H. Kogelnik et al., Appl. Phys. Lett. 18, 152 (1971); M. Canva et al., Appl. Opt., 34, 428 (1995)).
Recent work has demonstrated gain-narrowed photoluminescence spectra with full widths at half maxima (FWHM) of 40-60 .ANG. in response to a short pulse laser excitation, typically 1 .mu.J in a 10 ns pulse. (Materials Research Society 1997 Spring Meeting, Abstracts H1.1, H1.6, H2.1, H2.2, H2.3.) Such work is potentially applicable to electrically pumped organic solid state lasers ("plastic lasers"). If realized, such devices could offer low cost and ease of integration of laser sources onto either conventional semiconductor circuitry or lightweight plastic substrates.
Spun-on polymeric materials, however, do not exhibit particularly good thickness uniformity, ability to achieve extremely high materials purity, and ease of integration with other conventional semiconductor fabrication processes.
In the field of organic light emitting devices (OLEDs) for flat panel display applications, small molecule OLEDs currently offer better operating lifetimes by an order of magnitude over their spin-coated, polymeric analogs. (L. J. Rothberg et al., "Status of and Prospects for Organic Electroluminescence",J. Mater. Res. 1996, 11:3174; N. C. Greenham et al., "Semiconductor Physics of Conjugated Polymers", Solid State Physics 1995, 49:1.)
However, there has been no known demonstration of laser action in a vacuum-deposited organic thin film structure. Furthermore, there is considerable skepticism about the realization of small-molecule organic lasers because of quenching processes which can occur in such materials. Such quenching processes are observed at high carrier densities and lead to decreased photoluminescence quantum efficiency. For example, bimolecular reactions in Alq, films have been found to cause the quantum efficiency of photoluminescence to begin to decrease at incident intensities above 10.sup.14 photons/cm.sup.2. (D. Y. Zang et al., Appl. Phys. Lett. 60 (2), 189, 1992.)